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M Nishimura

Publications and source records attributed to M Nishimura.

At least 1,423 records · Page 79Linked to original sources
PubMed1976

Temperature-jump-induced release of hydrogen ions from chloroplasts and its relaxation characteristics in the presence of ionophores.

Temperature-jump-induced absorption changes of a bromocresol purple in chloroplast suspensions in the dark were studied. After a rapid rise in temperature (less than 10 mus), a slow absorbance decrease of bromocresol purple (t1/2 approximately 0.2 s) following a fast absorbance decrease of chloroplasts and bromocresol purple (t1/2 less than 1 ms) was observed. The slow absorbance decrease corresponds to acidification of the suspending medium, indicating H+ efflux from chloroplasts after the temperature jump. Nigericin and gramicidin D suppressed the slow absorbance change completely in the presence of 10 mM KC1, while valinomycin did not affect it. The fast absorbance change was not affected by the above ionophores. 3-(3,4-dichlorophenyl)-1,1-dimethylurea also diminished the slow absorbance change.

Biological Transport, Active↗
PubMed1976

The use of d-limonene preparation as a dissolving agent of gallstones.

The dissolving mixture is administered through a choledochal drain to treat postoperatively retained cholesterol gallstones. It is prepared by mixing 97.0 parts of d-limonene with 2.1 parts of polysorbate 80 and 0.9 part of sorbitan monooleate, a mixture of which may easily reach the surface of the gallstones which are wetted by bile. The d-limonene preparation was found to be safe both in laboratory experiments and clinical trials. Before applying the preparation, the usual choledochal drain must be replaced with a recently developed catheter made from epichlorohydrine rubber, which is chemically resistant to the preparation. Three cases of retained gallstones are described where the preparation was successfully used. In the fourth case treatment with the preparation was tried in lieu of surgery but was not successful due to other complications. However, some dissolution of retained stones was observed. There were no postoperative complaints in the long-term follow-up of some cases for more than 2 yr after treatment with the preparation. This procedure promises to be of value because retained cholesterol stones may be dissolved without the necessity of further surgery.

Adult↗
PubMed1976

Isolation and some properties of NAD+ reductase of the green photosynthetic bacterium Prosthecochloris aestuarii.

NAD+ reductase of the green photosynthetic bacterium Prosthecochloris aestuarii was isolated and purified by ammonium sulfate fractionation, DEAE-cellulose column chromatography, and Sephadex G-200 gel filtration. This enzyme is an FAD-containing flavoprotein and has absorption maxima at 485 (shoulder0 452, 411, and 385 nm (the 411 nm band is due to cytochrome). The molecular weight of the enzyme as determined by gel filtration using Sephadex G-200 is 119,000. The enzyme catalyzes the reduction of NAD+ and NADP+ by photoreduced spinach ferredoxin or reduced benzyl viologen...

2,6-Dichloroindophenol↗
PubMed1976

Light-induced oxidation-reduction reactions of cytochromes in the green sulfur photosynthetic bacterium Prosthecochloris aesturarii.

The light-induced oxidation-reduction reactions of cytochromes in intact cells, starved cells, and chlorobium vesicle fractions of the green sulfur photosynthetic bacterium Prosthecochloris aesturarii were studied under anaerobic conditions. On the basis of both kinetic and spectral properties, at least three cytochrome species were found to be involved in the light-induced oxidation-reduction reactions of intact cells. These cytochromes were designated according to the positions of alpha-band maxima as C555 (rapid and slow components) and C552 (intermediate). By comparing the light-minus-dark difference spectra with the reduced-minus-oxidized difference spectra of purified cytochromes of this organism, rapid component C555 and intermediate component C552 are suggested to correspond to the purified cytochromes c-555(550) and c-551.5, respectively. Although the identity of the slow-phase component is uncertain, one possibility is that the slow phase is due to the bound form of c-555(550). In substrate-depleted (starved) cells, only one cytochrome species, C555 remained in the reduced state in the dark and oxidized upon actinic illumination. This corresponds to the rapid C555 component in intact cells. In the case of chlorobium vesicle fractions, one cytochrome species having an alpha-band maximum at 554 nm was oxidized by actinic light. The effects of several inhibitors on the absorbance changes of intact cells were studied. Antimycin A decreased the rate of the dark reduction of rapid C555 component. The complex effects of CCCP (carbonyl cyanide m-chlorophenylhydrazone) on the oxidation-reduction reactions of cytochromes were interpreted as the results of inhibition of the electron donation to oxidized C552 and C555 (slow), and a shift of the dark steady-state redox levels of cytochromes. Based on these findings, it is suggested that the rapid C555 component is located in a cyclic electron transfer pathway. The other two cytochromes, C552 and C555 (slow), may be located in non-cyclic electron transfer pathways and receive electrons from exogenous substrates such as sodium sulfide. A tentative scheme for the electron transfer system in Prosthecochloris aestuarii is presented and its nature is discussed.

Antimycin A↗
PubMed1976

Isolation of intact chloroplasts and other cell organelles from spinach leaf protoplasts.

Freshly prepared spinach leaf protoplasts were gently ruptured by mechanical shearing followed by sucrose density gradient centrifugation to separate constituent cell organelles. The isolation of intact Class I chloroplasts (d = 1.21) in high yield, well separated from peroxisomes and mitochondria, was evidenced by the specific localization of ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39), NADP triose-P dehydrogenase (EC 1.2.1.9), and carbonic anhydrase (EC 4.2.1.1) in the fractions. A clear separation of chloroplastic ribosomes from the soluble cytoplasmic ribosomes was also demonstrated by the band patterns of constituent RNA species in the polyacrylamide gel electrophoresis. Localization of several enzyme activities specific to leaf peroxisomes, e.g. catalase (EC 1.11.1.6), glycolate oxidase (EC 1.1.3.1), glyoxylate reductase (EC 1.1.1.26), glutamate glyoxylate aminotransferase (EC 2.6.1.4), serine glyoxylate aminotransferase, and alanine glyoxylate aminotransferase (EC 2.6.1.12) in the peroxisomal fractions (d = 1.25), was demonstrated. Overall results show the feasibility of the method for the isolation of pure organelle components in leaf tissues.

Journal Article↗
PubMed1976

Immunotherapy of cancer patients with Bacillus Calmette-Guérin: summary of four years of experience in Japan.

Active immunotherapy with living BCG was conducted on 98 patients with various types of cancer. The candidates for this therapy were patients with residual or inoperable cancer of the colorectum, liver, breast, biliary tract, lung, and other organs with a follow-up of 4-58 months. Eleven of the 98 (11%) were able to survive for as long as 37-58 months (mean survival time 42.5 months) because of this treatment and are still living. Another 11 patients are also alive more than 24 months after starting treatment. Thirty-seven patients, however, succumbed within 12 months despite BCG immunotherapy. On the other hand, 37 patients in the control group, who shared the same clinical status and did not receive BCG therapy during this period, underwent unhappy courses for 2-12 months (mean survival time 8.7 months). The pretreatment immunoresponsiveness of these 98 patients was suppressed, as measured by the following immunologic parameters: T-cell subpopulation in the peripheral blood, stimulation index of PHA, and skin tests to DNCB, KLH, PPD, and PHA. All of these parameters improved shortly after initiation of BCG injections in 22 patients who survived more than 24 months. In contrast, in patients who died within 12 months, immunoresponsiveness remained suppressed throughout the course. This result has suggested that there was an apparent correlation between the effectiveness of BCG and immunoresponsiveness. In addition, a good correlation was observed between the duration of inflammatory reactions at BCG injection sites and clinical prognoses. Moreover, it was shown that a relatively high amount of BCG (20-80 mg as an initial dosage) and repeated injections of living BCG were necessary to obtain a sufficient enhancing effect on the immunocompetency of these late-stage cancer patients. The most conventional criterion used to determine an optimal time for booster injections of BCG was measurement of the PPD-evoked skin reaction at the BCG injection site, that is, Koch's phenomenon. When a marked flare-up reaction of more than 2.5 X 2.5 cm in size was observed, the effect of BCG was considered to be continuing, and no additional booster injection was needed. The mean interval between the first and second BCG injections was 6.2+/-1.1 months in patients who survived more than 2 years. In contrast, the duration of this reaction was only transient in ineffective cases. The most frequent side effects of this therapy were fever and malaise; these complications occurred in 62% of the cases. No severe side effects, such as dissemination, anaphylactic shock, or granulomatous hepatitis, have been experienced throughout this study, even in patients to whom a total dosage of more than 200 mg of living BCG were injected.

Adult↗
PubMed1975

Electron microscopic observations on the cholesterol distributed in the epithelial cells of the gallbladder.

Epithelial cells of eight human gallbladders with cholesterosis were examined. In the supranuclear portion of the epithelial cells of one case, many spicular, circular and plate-like crystalline structures are present. Spicular and circular structures have not a limiting membrane, but plate-like structures are apparently bounded by a limiting membrane that clearly shows trilamellar structure. After digitonin treatment, the spicular and circular crystalline structures become denser. On the other hand, the plate-like structures do not become denser by digitonization. In the epithelial cells that contain no crystalline structure, there also occur many reaction precipitates after digitonization. These findings may suggest that free cholesterol is highly present in the epithelial cells of gallbladder with cholesterosis and that it, in some case, precipitates in the form of spicular or circular structure for the rapid fixation process.

Cholesterol↗
PubMed1975

Nature of photochemical reactions in chromatophores of Chromatium D. III. Heterogeneity of the photosynthetic units.

The effect of isooctane extraction on photooxidation of c-type cytochromes was investigated in Chromatium chromatophores. Photooxidation of cytochrome c-555 was not affected by isooctane-extraction was abolished by thorough extraction of ubiquinone-7, but the quantum yield of the cytochrome photooxidation remained unchanged until 90% of the total ubiquinone was extracted. The photooxidation of cytochrome c-552 was recovered by the addition of ubiquinone-7 but not by menaquinone. A dark incubation of sufficient length was needed for maximal quantum yield of cytochrome c-555 photooxidation in the presence of 30 mM ascorbate. It is proposed that there are two types of photosynthetic units (or associations of molecules involved in the primary redox reactions) in Chromatium chromatophores. The combinations of primary electron donor-reaction center chlorophyll-primary electron acceptor may be cytochrome c-552-P890=ubiquinone in one type and cytochrome c-555-P890-X in another.

Ascorbic Acid↗
PubMed1975

Photosynthetic activities of spinach leaf protoplasts.

Photosynthetic activities of protoplasts isolated from spinach leaf (Spinacia oleracea L.) were investigated. The protoplasts were stable up to 9 hr, without loss of the original activity of CO(2) fixation (33-75 mumoles CO(2)/mg Chl.hr) and light-dependent O(2) evolution (33-40 mumoles O(2)/mg Chl.hr), when stored in 0.8 m mannitol-0.05 m N-tris (hydroxymethyl)-methylglycine-NaOH buffer, pH 7, at 4 C in dark. The optimum pH of 8.5 for CO(2) fixation reaction carried out in the present experimental condition employed is about the same as that reported for intact spinach chloroplasts. The CO(2) concentration for half-maximal rate of CO(2) fixation by protoplasts. "Km (CO(2))," were determined to be 19.8 mum (pH 7) and 42 mum (pH 8.5) and are similar to those observed for intact spinach chloroplasts. Protoplasts showed postillumination CO(2) fixation. Over-all results indicate that spinach protoplasts are as active as the intact plant leaf tissues in their photosynthetic activities.

Journal Article↗